Post-acute care in nursing homes (NHs) is common, costly, and variable in quality. While physicians are often seen as integral to improving care coordination and transitions in care, little is known about the role of physicians within NHs in th outcomes of patients who transition from hospitals to post-acute care at these facilities. Hospitals have increasingly adopted strategies to improve patient outcomes and reduce costs- concentrating inpatient care among fewer physicians who specialize in hospital care and using organizational strategies that provide more hands-on oversight of physicians. However, the effect of similar strategies in the NH setting is unknown. Additionally, because post-acute care NH patients tend to be older and sicker, concerns have been raised about whether reducing continuity of care with primary care providers will lead to more challenging transitions to the community for these patients. The current project will evaluate the degree to which NHs concentrate their patient care among a few versus many physicians, the degree to which a NH's physicians specialize in providing NH care, and the organizational strategies NHs use to manage physician relationships (such as employment or contractual arrangements, credentialing, or oversight) as potential mechanisms to improve the outcomes of patients receiving post-acute care in NHs. To accomplish this research, I will use an existing database of a nationally representative sample of NHs merged with institutional Part A Medicare claims, the nursing home Minimum Data Set, and survey data on NH physician organizational strategies, expanding this database to include all Medicare Part B claims for physicians in the sample to measure physician specialization within NHs. Working under the mentorship of experts in post-acute care policy and NH medical staff organization, I will: (1) measure the association between the degree to which HNs concentrate their patient care among a few versus many physicians and post-acute care outcomes (patient readmission to the hospital within 30-days of NH admission and successful discharge to the community); (2) measure the effect of physician specialization in NH care on these outcomes; and (3) measure the effect of NHs' organizational strategies for physicians on these outcomes. When complete, these studies will provide new key information regarding a modifiable aspect of the post-acute care delivery system to inform NH policy and practice. This work will also help me establish a set of skills to become an independent investigator evaluating the value of various physician practice models to optimize care delivery for aging patients with multiple chronic conditions.